Add GdkPangoRenderer, a subclass of PangoRenderer targeting GDK drawables.

Sat Nov 20 15:13:51 2004  Owen Taylor  <otaylor@redhat.com>

	* gdk/gdkpango.[ch]: Add GdkPangoRenderer, a subclass of
	PangoRenderer targeting GDK drawables. Use to implement the old
	gdk_draw_layout() and friends.

	* gdk/gdkdraw.c gdk/gdkdrawable.h gdk/gdkwindow.c gdk/gdkpixmap.c:
	Add gdk_draw_glyphs_transformed() gdk_draw_trapezoids() and
	the corresponding members of GdkDrawableClass. Add a fallback
	implementation of gdk_draw_trapezoids() in terms of pixbufs.

	* gdk/gdkwindowing.h gdk/x11/gdkg-x11.h: Add
	_gdk_windowing_gc_get_foreground() to enable the fallback
	trapezoid implementation.

	* gdk/x11/gdkdrawable-x11.c gdk/x11/gdkdisplay-x11.h: Implement
	draw_glyph_transformed,	draw_trapezoids.

	* gdk/x11/gdkdrawable-x11.[ch]: Add
	_gdk_x11_drawable_draw_xtrapezoids, _gdk_x11_drawable_draw_xft_glyphs
	for use of GdkX11Renderer.

	* gdk/x11/gdkgc-x11.c gdk/x11/gdkprivate-x11.h: Implement
	GDK_TILED, GDK_STIPPLED, GDK_OPAQUE_STIPPLED in the RENDER codepath.

	* gdk/gdkpango-x11.c: Add GdkX11Renderer... a subclass of
	PangoXftRenderer that does tiles/stipples and fallback rendering
	of trapezoids without the RENDER extension.

	* gdk/gdkpango-x11.c gdk/x11/gdkscreen-x11.[ch] _gdk_x11_renderer_get:
	Add _gdk_x11_renderer_get() to get a singleton GdkX11Renderer
	for the screen.

	* gdk/x11/gdkdrawable-x11.c (get_impl_drawable): Fix a None/NULL
	confusion.

	* gtk/gtklabel.[ch] gtk/gtk.symbols: Add gtk_label_set/get_angle(),
	and an ::angle property.

	* gtk/gtklabel.c: Remove #if 0'd dead code gtk_label_paint_word().

	* gtk/gtktextdisplay.c: Switch to using a GtkTextRenderer subclass
	of GdkPangoRenderer for drawing.

	* gtk/gtktextlayout.[ch] gtk/gtktextdisplay.c: Switch to using
	gtk_attr_shape_new_with_data() to store backreferences to
	embedded pixmaps and widgets. Leave line_display->shaped_objects
	around for backwords compatibility.

	* gdk/gdkpango.[ch] (gdk_pango_context_set_colormap): Describe
	as deprecated, remove implementation.

	* gtk/gtkwidget.c (gtk_widget_create_pango_context): Remove
	call to gdk_pango_context_set_colormap.

	* demos/gtk-demo/Makefile.am demos/gtk-demo/rotated_text.c: Add
	a demo showing drawing rotated text.

	* tests/testgtk.c: Add a rotated-label test, and also a rotated
	drawing test (differs from demos/gtk-demo/rotated_text by also
	using a tile)

2 files changed, 143 insertions, 0 deletions

diff --git a/demos/gtk-demo/Makefile.am b/demos/gtk-demo/Makefile.am
index 65a52ca9b8..dd904195be 100644
--- a/demos/gtk-demo/Makefile.am
+++ b/demos/gtk-demo/Makefile.am
@@ -22,6 +22,7 @@ demos =						\
 	menus.c					\
 	panes.c					\
 	pixbufs.c				\
+	rotated_text.c				\
 	sizegroup.c				\
 	stock_browser.c				\
 	textview.c				\
diff --git a/demos/gtk-demo/rotated_text.c b/demos/gtk-demo/rotated_text.c
new file mode 100644
index 0000000000..1c37548dd2
--- /dev/null
+++ b/demos/gtk-demo/rotated_text.c
@@ -0,0 +1,142 @@
+/* Rotated Text
+ *
+ * This demo shows how to use GDK and Pango to draw rotated and transformed
+ * text. The use of GdkPangoRenderer in this example is a somewhat advanced
+ * technique; most applications can simply use gdk_draw_layout(). We use
+ * it here mostly because that allows us to work in user coordinates - that is,
+ * coordinates prior to the application of the transformation matrix, rather
+ * than device coordinates.
+ *
+ * As of GTK+-2.6, the ability to draw transformed and anti-aliased graphics
+ * as shown in this example is only present for text. With GTK+-2.8, a new
+ * graphics system called "Cairo" will be introduced that provides these
+ * capabilities and many more for all types of graphics.
+ */
+#include <math.h>
+#include <gtk/gtk.h>
+
+static GtkWidget *window = NULL;
+
+static gboolean
+rotated_text_expose_event (GtkWidget      *widget,
+			   GdkEventExpose *event,
+			   gpointer	   data)
+{
+#define RADIUS 150
+#define N_WORDS 10
+#define FONT "Sans Bold 27"
+  
+  PangoRenderer *renderer;
+  PangoMatrix matrix = PANGO_MATRIX_INIT;
+  PangoContext *context;
+  PangoLayout *layout;
+  PangoFontDescription *desc;
+
+  int width = widget->allocation.width;
+  int height = widget->allocation.height;
+  double device_radius;
+  int i;
+
+  /* Get the default renderer for the screen, and set it up for drawing  */
+  renderer = gdk_pango_renderer_get_default (gtk_widget_get_screen (widget));
+  gdk_pango_renderer_set_drawable (GDK_PANGO_RENDERER (renderer), widget->window);
+  gdk_pango_renderer_set_gc (GDK_PANGO_RENDERER (renderer), widget->style->black_gc);
+
+  /* Set up a transformation matrix so that the user space coordinates for
+   * the centered square where we draw are [-RADIUS, RADIUS], [-RADIUS, RADIUS]
+   * We first center, then change the scale */
+  device_radius = MIN (width, height) / 2.;
+  pango_matrix_translate (&matrix,
+			  device_radius + (width - 2 * device_radius) / 2,
+			  device_radius + (height - 2 * device_radius) / 2);
+  pango_matrix_scale (&matrix, device_radius / RADIUS, device_radius / RADIUS);
+
+  /* Create a PangoLayout, set the font and text */
+  context = gtk_widget_create_pango_context (widget);
+  layout = pango_layout_new (context);
+  pango_layout_set_text (layout, "Text", -1);
+  desc = pango_font_description_from_string (FONT);
+  pango_layout_set_font_description (layout, desc);
+  pango_font_description_free (desc);
+
+  /* Draw the layout N_WORDS times in a circle */
+  for (i = 0; i < N_WORDS; i++)
+    {
+      GdkColor color;
+      PangoMatrix rotated_matrix = matrix;
+      int width, height;
+      double angle = (360. * i) / N_WORDS;
+
+      /* Gradient from red at angle == 60 to blue at angle == 300 */
+      color.red   = 65535 * (1 + cos ((angle - 60) * M_PI / 180.)) / 2;
+      color.green = 0;
+      color.blue  = 65535  - color.red;
+    
+      gdk_pango_renderer_set_override_color (GDK_PANGO_RENDERER (renderer),
+					     PANGO_RENDER_PART_FOREGROUND, &color);
+                                             
+      pango_matrix_rotate (&rotated_matrix, angle);
+
+      pango_context_set_matrix (context, &rotated_matrix);
+    
+      /* Inform Pango to re-layout the text with the new transformation matrix */
+      pango_layout_context_changed (layout);
+    
+      pango_layout_get_size (layout, &width, &height);
+      pango_renderer_draw_layout (renderer, layout,
+				  - width / 2, - RADIUS * PANGO_SCALE);
+    }
+
+  /* Clean up default renderer, since it is shared */
+  gdk_pango_renderer_set_override_color (GDK_PANGO_RENDERER (renderer),
+					 PANGO_RENDER_PART_FOREGROUND, NULL);
+  gdk_pango_renderer_set_drawable (GDK_PANGO_RENDERER (renderer), NULL);
+  gdk_pango_renderer_set_gc (GDK_PANGO_RENDERER (renderer), NULL);
+
+  /* free the objects we created */
+  g_object_unref (layout);
+  g_object_unref (context);
+  
+  return FALSE;
+}
+
+GtkWidget *
+do_rotated_text (GtkWidget *do_widget)
+{
+  GtkWidget *drawing_area;
+  
+  if (!window)
+    {
+      const GdkColor white = { 0, 0xffff, 0xffff, 0xffff };
+      
+      window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
+      gtk_window_set_screen (GTK_WINDOW (window),
+			     gtk_widget_get_screen (do_widget));
+      gtk_window_set_title (GTK_WINDOW (window), "Rotated Text");
+
+      g_signal_connect (window, "destroy", G_CALLBACK (gtk_widget_destroyed), &window);
+
+      drawing_area = gtk_drawing_area_new ();
+      gtk_container_add (GTK_CONTAINER (window), drawing_area);
+
+      /* This overrides the background color from the theme */
+      gtk_widget_modify_bg (drawing_area, GTK_STATE_NORMAL, &white);
+
+      g_signal_connect (drawing_area, "expose-event",
+			G_CALLBACK (rotated_text_expose_event), NULL);
+
+      gtk_window_set_default_size (GTK_WINDOW (window), 2 * RADIUS, 2 * RADIUS);
+    }
+
+  if (!GTK_WIDGET_VISIBLE (window))
+    {
+      gtk_widget_show_all (window);
+    }
+  else
+    {
+      gtk_widget_destroy (window);
+      window = NULL;
+    }
+
+  return window;
+}